IB Bio HL Unit 1

Ribosomes

in all cells and site of protein synthesis. translate genetic information from RNAs to amino acids which are folded into proteins. Can be found free-floating in the cytoplasm or attached to ER

Nucleoid

just in prokaryotic cells, store DNA and genetic material. not separated from the rest of the cell by cytoplasm. Irregularly shaped does not have a defined size, shape or location.

lysosome

located in the cytoplasm in eukaryotic cells. have enzymes that break down and digest material

exocytosis

process of the cell vacuoles contents get released into the exterior enviornment through fusion of the vacuole membrane and the cell membrane.

vacuole

in the cytoplasm, enclosed by a membrane typically filled with fluid

eukaryote

contains a nucleus and other membrane bound organelles

membrane bound

enclosed by a membrane

mitochondrion

convert nutrients into chemical energy. located in the cytoplasm

cytoplasm

jelly like substance within a cell surrounded by the cell membrane. it serves as a medium for cellular activity and provides structural support.

cytosol

the aqueous component of cytoplasm

nucleus

membrane bound organelle, found only in eukaryotic cells and contains the cells genetic DNA. located in the central region of the cell

Nuclear Envelope

a double membrane that encloses the nucleus separating the genetic material from the cytoplasm.

Smooth endoplasmic reticulum

a network of membrane bound tubules. DOES NOT have ribosomes. NOT involved in protein synthesis. metabolizes and detoxifies. located

Golgi Apparatus

processes and packages proteins and lipids received from the ER. located near the ER

prokaryotic

NO nucleus, smaller and simpler than eukaryotic cells.

vesicle

composed of a lipid bilayer used to transport things between organelles.

Organic Chemistry

carbon molecules

carbon

element- non metal

Covalent bond

a chemical bond where atoms share electrons

Deoxyribose

sugar derived from ribose by replacing a hydroxyl group with hydrogen.

nitrogenous base

organic molecule containing nitrogen that acts as a base and is a fundamental component of DNA and RNA, forming part of nucleotides

Valence electrons

electrons on the outermost shell

purine

a colorless crystalline compound with basic properties, forming uric acid on oxidation.

tetravalence

the capacity of an atom to form four covalent bonds with other atoms

Adenine

a compound which is one of the four constituent bases of nucleic acids. A purine derivative, it is paired with thymine in double-stranded DNA.

non-polar bonds

a covalent bond where two atoms share electrons equally due to having similar or identical electronegativity

guanine

one of the four constituent bases of nucleic acids. A purine derivative, it is paired with cytosine in double-stranded DNA

metabolism

the chemical processes that occur within a living organism in order to maintain life.

pyrimidine

a colorless crystalline compound with basic properties

thymine

one of the four constituent bases of nucleic acids. A pyrimidine derivative, it is paired with adenine in double-stranded DNA

cytosine

a compound found in living tissue as a constituent base of nucleic acids. It is paired with guanine in double-stranded DNA

anabolic

metabolic processes that involve building up complex molecules from simpler ones, requiring energy input

Uracil

a compound found in living tissue as a constituent base of RNA. In DNA its place is taken by thymine

dehydration synthesis

a chemical process where two molecules are joined together to form a larger molecule, accompanied by the removal of a water molecule

polynucleotide

a long chain of nucleotide building blocks

phosphodiester

a strong covalent bond that links nucleotides together, forming the backbone of DNA and RNA molecules

catabolic

describes the metabolic processes of breaking down complex molecules into simpler ones, a process that releases energy and is essential for life

sugar-phosphate backbone

the structural framework of nucleic acids like DNA and RNA, consisting of alternating sugar and phosphate groups linked by covalent phosphodiester bonds

hydrolysis

a chemical reaction where water is used to break a chemical bond in a compound, dividing it into two or more smaller molecules

double helix

a pair of parallel helices intertwined about a common axis, especially that in the structure of the DNA molecul

monomer

a small molecule that acts as a building block, capable of bonding with identical or similar molecules to form large, complex structures called polymers

anti parallel

describes a situation where two parallel structures are oriented in opposite directions

polymer

a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together

5’ and 3’ ends

the two ends of a DNA or RNA strand

macromolecule

a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer

complementary base pairing

adenine (A) always pairs with thymine (T), and cytosine (C) always pairs with guanine (G)

nucleic acids

essential biomolecules, primarily DNA and RNA, that carry genetic information and play a crucial role in protein synthesis

hydrogen bonding

a strong intermolecular force where a hydrogen atom bonded to a highly electronegative atom (like oxygen, nitrogen, or fluorine) is attracted to a lone pair of electrons on another electronegative atom in a different molecule

Deoxyribonucleic acid

DNA

ribonucleic acids

RNA

function of DNA and RNA

DNA stores genetic information as a stable, long-term blueprint for the cell, while RNA translates this information into proteins

Hershey-Chase experiment

used radioactively labeled viruses to prove that DNA is the genetic material, not protein

nucleotide

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

Chargaff’s ratios

in a DNA molecule, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C). This means that the ratio of A to T is roughly 1:1, and the ratio of G to C is also roughly 1:1, a pattern that is consistent across different species and was crucial in determining the structure of DNA

CHONP

a partial acronym representing the essential elements Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and Phosphorus (P), which are the fundamental building blocks of biological molecules. These elements are found in carbohydrates, lipids, proteins, and nucleic acids

tetranucleotide hypothesis

incorrectly stated that DNA was composed of repeating, identical tetramers of the four bases (adenine, guanine, cytosine, and thymine) in equal amounts

Rosalind Franklin

applied X-ray diffraction techniques to DNA fibers, producing high-resolution images that revealed the helical structure of the molecule

phosphate group

consists of a central phosphorus atom bonded to four oxygen atoms

pentose sugar

a monosaccharide (simple sugar) with five carbon atoms. They are crucial in biology, particularly as components of nucleic acids like DNA and RNA

ribose

a sugar of the pentose class which occurs widely in nature as a constituent of nucleosides and several vitamins and enzymes. In RNA

prebiotic earth

the period on early Earth before the emergence of life, where chemical and physical conditions fostered the abiotic (non-living) synthesis of organic molecules and other precursors to life

premordial soup

a solution rich in organic compounds in the primitive oceans of the earth, from which life is hypothesized to have originated

spontaneous generation

the supposed production of living organisms from nonliving matter, as inferred from the apparent appearance of life in some supposedly sterile environments

Pastuer

falsified the claim of spontaneous generation with his chicken broth in a squiggly glass tube.

redi’s experiment

disproved the theory of spontaneous generation (also known as abiogenesis) for maggots on decaying meat

Organic molecules

carbon-based compounds that are fundamental to life, typically containing carbon and hydrogen atoms and often forming long chains or rings

Miller-Urey experiment

simulated early Earth conditions in 1952, creating amino acids and other organic building blocks from inorganic molecules like methane, ammonia, and water vapor

vesicle/spherical bilayer

two-dimensional lipid membrane that forms a hollow sphere, enclosing an aqueous solution

LUCA

an abbreviation for the Last Universal Common Ancestor of all modern life on Earth, including bacteria, archaea, and eukaryotes (like humans and plants). It was a single cellular organism from which all currently living organisms are descended

hydrothermal vents

underwater hot springs where superheated, mineral-rich water, heated by magma, emerges from the ocean floor, often forming chimneys and supporting unique ecosystems based on chemosynthesis rather than sunlight

cell theory

the fundamental biological principle that states all living organisms are made of cells, the cell is the basic unit of structure and organization in living things, and all cells come from pre-existing cells

Light microscope

a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects

Flagella

a slender threadlike structure, especially a microscopic appendage that enables many protozoa, bacteria, spermatozoa, etc. to swim

centrioles

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division

Cilia

a short microscopic hairlike vibrating structure found in large numbers on the surface of certain cells, either causing currents in the surrounding fluid, or, in some protozoans and other small organisms, providing propulsion

nucleolus

a small dense spherical structure in the nucleus of a cell during interphase

nuclear pore

a protein-lined channel in the nuclear envelope that regulates the movement of molecules between the nucleus and the cytoplasm of a cell

Atypical cell structure

cells with unusual forms or organization that allow them to perform specialized functions

compartmentalization

the division of a cell or organism into distinct regions, compartments, or structures to organize specific functions and increase efficiency

red blood cells

specialized cells in your blood that transport oxygen from the lungs to tissues and carry carbon dioxide waste back to the lungs. Lacking a nucleus and mitochondria

phloem sieve tubes

lack a nucleus and most organelles at maturity, relying on companion cells for metabolic support. The sieve elements are connected by sieve plates with pores, which facilitate the flow of phloem sap under hydrostatic pressure created by water entering the tubes via osmosis

striated skeletal muscle cells

multinucleated and under voluntary control, meaning we consciously control their movements

aseptic fungal hyphae cells

multinucleate filaments that lack internal cell walls (septa) and have a continuous cytoplasm, functioning more like a single large cell than a chain of separate cells

Processes of life

movement, metabolism, nutrition, response to stimuli, homeostasis, growth, reproduction

endosymbiosis

symbiosis in which one of the symbiotic organisms lives inside the other. Evidence: similarities in DNA, ribosomes, and membranes between these organelles and prokaryotes